Electrostatographic carrier beads and method of making

ABSTRACT

Electrophotographic carrier beads, comprising steel shot as a core material, are coated and then cured by a single-pass manufacturing process, using a coating liquid consisting of a water-based modified epoxy whose three-dimensional, highly cross-linked cellular structure, is packed with a fluoropolymer. This water-based carrier coating makes use of the water-based modified epoxy described in U.S. Pat. No. 4,212,781. 
     For a first example, this epoxy material is converted to an aqueous dispersion by mixing with deionized water, an aminoplast cross-linking resin (hexamethoxymethylmelamine), fluorinated ethylene-propylene, and chromium oxide. 
     This aqueous dispersion is coated onto steel shot by a single-pass fluidized bed manufacturing process. 
     For a second example, this epoxy material is converted to an aqueous dispersion by mixing with deionized water, said aminoplast cross-linking agent, said fluorinated ethylene-propylene and a second fluoropolymer, polytetrafluoroethylene. 
     This aqueous dispersion is coated onto steel shot in the same manner.



